/
x509.c
1646 lines (1429 loc) · 44.7 KB
/
x509.c
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/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/list.h>
#include <ipxe/malloc.h>
#include <ipxe/asn1.h>
#include <ipxe/crypto.h>
#include <ipxe/md5.h>
#include <ipxe/sha1.h>
#include <ipxe/sha256.h>
#include <ipxe/rsa.h>
#include <ipxe/rootcert.h>
#include <ipxe/x509.h>
/** @file
*
* X.509 certificates
*
* The structure of X.509v3 certificates is documented in RFC 5280
* section 4.1.
*/
/* Disambiguate the various error causes */
#define ENOTSUP_ALGORITHM \
__einfo_error ( EINFO_ENOTSUP_ALGORITHM )
#define EINFO_ENOTSUP_ALGORITHM \
__einfo_uniqify ( EINFO_ENOTSUP, 0x01, "Unsupported algorithm" )
#define ENOTSUP_EXTENSION \
__einfo_error ( EINFO_ENOTSUP_EXTENSION )
#define EINFO_ENOTSUP_EXTENSION \
__einfo_uniqify ( EINFO_ENOTSUP, 0x02, "Unsupported extension" )
#define EINVAL_ALGORITHM \
__einfo_error ( EINFO_EINVAL_ALGORITHM )
#define EINFO_EINVAL_ALGORITHM \
__einfo_uniqify ( EINFO_EINVAL, 0x01, "Invalid algorithm type" )
#define EINVAL_ALGORITHM_MISMATCH \
__einfo_error ( EINFO_EINVAL_ALGORITHM_MISMATCH )
#define EINFO_EINVAL_ALGORITHM_MISMATCH \
__einfo_uniqify ( EINFO_EINVAL, 0x04, "Signature algorithm mismatch" )
#define EINVAL_PATH_LEN \
__einfo_error ( EINFO_EINVAL_PATH_LEN )
#define EINFO_EINVAL_PATH_LEN \
__einfo_uniqify ( EINFO_EINVAL, 0x05, "Invalid pathLenConstraint" )
#define EINVAL_VERSION \
__einfo_error ( EINFO_EINVAL_VERSION )
#define EINFO_EINVAL_VERSION \
__einfo_uniqify ( EINFO_EINVAL, 0x06, "Invalid version" )
#define EACCES_WRONG_ISSUER \
__einfo_error ( EINFO_EACCES_WRONG_ISSUER )
#define EINFO_EACCES_WRONG_ISSUER \
__einfo_uniqify ( EINFO_EACCES, 0x01, "Wrong issuer" )
#define EACCES_NOT_CA \
__einfo_error ( EINFO_EACCES_NOT_CA )
#define EINFO_EACCES_NOT_CA \
__einfo_uniqify ( EINFO_EACCES, 0x02, "Not a CA certificate" )
#define EACCES_KEY_USAGE \
__einfo_error ( EINFO_EACCES_KEY_USAGE )
#define EINFO_EACCES_KEY_USAGE \
__einfo_uniqify ( EINFO_EACCES, 0x03, "Incorrect key usage" )
#define EACCES_EXPIRED \
__einfo_error ( EINFO_EACCES_EXPIRED )
#define EINFO_EACCES_EXPIRED \
__einfo_uniqify ( EINFO_EACCES, 0x04, "Expired (or not yet valid)" )
#define EACCES_PATH_LEN \
__einfo_error ( EINFO_EACCES_PATH_LEN )
#define EINFO_EACCES_PATH_LEN \
__einfo_uniqify ( EINFO_EACCES, 0x05, "Maximum path length exceeded" )
#define EACCES_UNTRUSTED \
__einfo_error ( EINFO_EACCES_UNTRUSTED )
#define EINFO_EACCES_UNTRUSTED \
__einfo_uniqify ( EINFO_EACCES, 0x06, "Untrusted root certificate" )
#define EACCES_OUT_OF_ORDER \
__einfo_error ( EINFO_EACCES_OUT_OF_ORDER )
#define EINFO_EACCES_OUT_OF_ORDER \
__einfo_uniqify ( EINFO_EACCES, 0x07, "Validation out of order" )
#define EACCES_EMPTY \
__einfo_error ( EINFO_EACCES_EMPTY )
#define EINFO_EACCES_EMPTY \
__einfo_uniqify ( EINFO_EACCES, 0x08, "Empty certificate chain" )
#define EACCES_OCSP_REQUIRED \
__einfo_error ( EINFO_EACCES_OCSP_REQUIRED )
#define EINFO_EACCES_OCSP_REQUIRED \
__einfo_uniqify ( EINFO_EACCES, 0x09, "OCSP check required" )
/** Certificate cache */
static LIST_HEAD ( x509_cache );
/**
* Free X.509 certificate
*
* @v refcnt Reference count
*/
static void x509_free ( struct refcnt *refcnt ) {
struct x509_certificate *cert =
container_of ( refcnt, struct x509_certificate, refcnt );
DBGC2 ( cert, "X509 %p freed\n", cert );
free ( cert->subject.name );
free ( cert->extensions.auth_info.ocsp.uri );
free ( cert );
}
/**
* Discard a cached certificate
*
* @ret discarded Number of cached items discarded
*/
static unsigned int x509_discard ( void ) {
struct x509_certificate *cert;
/* Discard the least recently used certificate for which the
* only reference is held by the cache itself.
*/
list_for_each_entry_reverse ( cert, &x509_cache, list ) {
if ( cert->refcnt.count == 0 ) {
list_del ( &cert->list );
x509_put ( cert );
return 1;
}
}
return 0;
}
/** X.509 cache discarder */
struct cache_discarder x509_discarder __cache_discarder ( CACHE_NORMAL ) = {
.discard = x509_discard,
};
/** "commonName" object identifier */
static uint8_t oid_common_name[] = { ASN1_OID_COMMON_NAME };
/** "commonName" object identifier cursor */
static struct asn1_cursor oid_common_name_cursor =
ASN1_OID_CURSOR ( oid_common_name );
/**
* Parse X.509 certificate version
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_version ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
int version;
int rc;
/* Enter version */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_EXPLICIT_TAG ( 0 ) );
/* Parse integer */
if ( ( rc = asn1_integer ( &cursor, &version ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot parse version: %s\n",
cert, strerror ( rc ) );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
/* Sanity check */
if ( version < 0 ) {
DBGC ( cert, "X509 %p invalid version %d\n", cert, version );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return -EINVAL_VERSION;
}
/* Record version */
cert->version = version;
DBGC2 ( cert, "X509 %p is a version %d certificate\n",
cert, ( cert->version + 1 ) );
return 0;
}
/**
* Parse X.509 certificate serial number
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_serial ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_serial *serial = &cert->serial;
int rc;
/* Record raw serial number */
memcpy ( &serial->raw, raw, sizeof ( serial->raw ) );
if ( ( rc = asn1_shrink ( &serial->raw, ASN1_INTEGER ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot shrink serialNumber: %s\n",
cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p issuer is:\n", cert );
DBGC2_HDA ( cert, 0, serial->raw.data, serial->raw.len );
return 0;
}
/**
* Parse X.509 certificate issuer
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_issuer ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_issuer *issuer = &cert->issuer;
int rc;
/* Record raw issuer */
memcpy ( &issuer->raw, raw, sizeof ( issuer->raw ) );
if ( ( rc = asn1_shrink ( &issuer->raw, ASN1_SEQUENCE ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot shrink issuer: %s\n",
cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p issuer is:\n", cert );
DBGC2_HDA ( cert, 0, issuer->raw.data, issuer->raw.len );
return 0;
}
/**
* Parse X.509 certificate validity
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_validity ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_validity *validity = &cert->validity;
struct x509_time *not_before = &validity->not_before;
struct x509_time *not_after = &validity->not_after;
struct asn1_cursor cursor;
int rc;
/* Enter validity */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse notBefore */
if ( ( rc = asn1_generalized_time ( &cursor,
¬_before->time ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot parse notBefore: %s\n",
cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p valid from time %lld\n",
cert, not_before->time );
asn1_skip_any ( &cursor );
/* Parse notAfter */
if ( ( rc = asn1_generalized_time ( &cursor,
¬_after->time ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot parse notAfter: %s\n",
cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p valid until time %lld\n",
cert, not_after->time );
return 0;
}
/**
* Parse X.509 certificate common name
*
* @v cert X.509 certificate
* @v name Common name to fill in
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_common_name ( struct x509_certificate *cert, char **name,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
struct asn1_cursor oid_cursor;
struct asn1_cursor name_cursor;
int rc;
/* Enter name */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Scan through name list */
for ( ; cursor.len ; asn1_skip_any ( &cursor ) ) {
/* Check for "commonName" OID */
memcpy ( &oid_cursor, &cursor, sizeof ( oid_cursor ) );
asn1_enter ( &oid_cursor, ASN1_SET );
asn1_enter ( &oid_cursor, ASN1_SEQUENCE );
memcpy ( &name_cursor, &oid_cursor, sizeof ( name_cursor ) );
asn1_enter ( &oid_cursor, ASN1_OID );
if ( asn1_compare ( &oid_common_name_cursor, &oid_cursor ) != 0)
continue;
asn1_skip_any ( &name_cursor );
if ( ( rc = asn1_enter_any ( &name_cursor ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot locate name:\n", cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
/* Allocate and copy name */
*name = zalloc ( name_cursor.len + 1 /* NUL */ );
if ( ! *name )
return -ENOMEM;
memcpy ( *name, name_cursor.data, name_cursor.len );
/* Check that name contains no NULs */
if ( strlen ( *name ) != name_cursor.len ) {
DBGC ( cert, "X509 %p contains malicious commonName:\n",
cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
return 0;
}
/* Certificates may not have a commonName */
DBGC2 ( cert, "X509 %p no commonName found:\n", cert );
return 0;
}
/**
* Parse X.509 certificate subject
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_subject ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_subject *subject = &cert->subject;
char **name = &subject->name;
int rc;
/* Record raw subject */
memcpy ( &subject->raw, raw, sizeof ( subject->raw ) );
asn1_shrink_any ( &subject->raw );
DBGC2 ( cert, "X509 %p subject is:\n", cert );
DBGC2_HDA ( cert, 0, subject->raw.data, subject->raw.len );
/* Parse common name */
if ( ( rc = x509_parse_common_name ( cert, name, raw ) ) != 0 )
return rc;
DBGC2 ( cert, "X509 %p common name is \"%s\":\n", cert, *name );
return 0;
}
/**
* Parse X.509 certificate public key information
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_public_key ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_public_key *public_key = &cert->subject.public_key;
struct asn1_algorithm **algorithm = &public_key->algorithm;
struct asn1_bit_string *raw_bits = &public_key->raw_bits;
struct asn1_cursor cursor;
int rc;
/* Record raw subjectPublicKeyInfo */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_shrink_any ( &cursor );
memcpy ( &public_key->raw, &cursor, sizeof ( public_key->raw ) );
DBGC2 ( cert, "X509 %p public key is:\n", cert );
DBGC2_HDA ( cert, 0, public_key->raw.data, public_key->raw.len );
/* Enter subjectPublicKeyInfo */
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse algorithm */
if ( ( rc = asn1_pubkey_algorithm ( &cursor, algorithm ) ) != 0 ) {
DBGC ( cert, "X509 %p could not parse public key algorithm: "
"%s\n", cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p public key algorithm is %s\n",
cert, (*algorithm)->name );
asn1_skip_any ( &cursor );
/* Parse bit string */
if ( ( rc = asn1_bit_string ( &cursor, raw_bits ) ) != 0 ) {
DBGC ( cert, "X509 %p could not parse public key bits: %s\n",
cert, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Parse X.509 certificate basic constraints
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_basic_constraints ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_basic_constraints *basic = &cert->extensions.basic;
struct asn1_cursor cursor;
int ca = 0;
int path_len;
int rc;
/* Enter basicConstraints */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse "cA", if present */
if ( asn1_type ( &cursor ) == ASN1_BOOLEAN ) {
ca = asn1_boolean ( &cursor );
if ( ca < 0 ) {
rc = ca;
DBGC ( cert, "X509 %p cannot parse cA: %s\n",
cert, strerror ( rc ) );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
asn1_skip_any ( &cursor );
}
basic->ca = ca;
DBGC2 ( cert, "X509 %p is %sa CA certificate\n",
cert, ( basic->ca ? "" : "not " ) );
/* Ignore everything else unless "cA" is true */
if ( ! ca )
return 0;
/* Parse "pathLenConstraint", if present and applicable */
basic->path_len = X509_PATH_LEN_UNLIMITED;
if ( asn1_type ( &cursor ) == ASN1_INTEGER ) {
if ( ( rc = asn1_integer ( &cursor, &path_len ) ) != 0 ) {
DBGC ( cert, "X509 %p cannot parse pathLenConstraint: "
"%s\n", cert, strerror ( rc ) );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
if ( path_len < 0 ) {
DBGC ( cert, "X509 %p invalid pathLenConstraint %d\n",
cert, path_len );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return -EINVAL;
}
basic->path_len = path_len;
DBGC2 ( cert, "X509 %p path length constraint is %u\n",
cert, basic->path_len );
}
return 0;
}
/**
* Parse X.509 certificate key usage
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_key_usage ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_key_usage *usage = &cert->extensions.usage;
struct asn1_bit_string bit_string;
const uint8_t *bytes;
size_t len;
unsigned int i;
int rc;
/* Mark extension as present */
usage->present = 1;
/* Parse bit string */
if ( ( rc = asn1_bit_string ( raw, &bit_string ) ) != 0 ) {
DBGC ( cert, "X509 %p could not parse key usage: %s\n",
cert, strerror ( rc ) );
return rc;
}
/* Parse key usage bits */
bytes = bit_string.data;
len = bit_string.len;
if ( len > sizeof ( usage->bits ) )
len = sizeof ( usage->bits );
for ( i = 0 ; i < len ; i++ ) {
usage->bits |= ( *(bytes++) << ( 8 * i ) );
}
DBGC2 ( cert, "X509 %p key usage is %08x\n", cert, usage->bits );
return 0;
}
/**
* Parse X.509 certificate subject alternative name
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_subject_alt_name ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_subject_alt_name *subject_alt_name = &cert->extensions.subject_alt_name;
struct asn1_cursor cursor;
struct asn1_cursor string_cursor;
int rc;
/* Mark extension as present */
subject_alt_name->present = 1;
DBGC ( cert, "X509 %p parsing subjectAltName\n", cert );
/* Enter GeneralNames */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
DBGC_HDA ( cert, 0, cursor.data, 128 );
INIT_LIST_HEAD ( &subject_alt_name->names );
/* Parse each name in turn */
while ( cursor.len ) {
memcpy ( &string_cursor, &cursor, sizeof ( string_cursor ) );
if ( ( rc = asn1_enter ( &string_cursor, ASN1_IMPLICIT_TAG ( 2 ) ) ) == 0 ) {
char* name = zalloc ( string_cursor.len + 1 );
memcpy ( name, string_cursor.data, string_cursor.len );
if ( strlen ( name ) != string_cursor.len ) {
DBGC ( cert, "X509 %p contains malicious subjectAltName\n",
cert );
return rc;
}
//DBGC ( cert, "X509 %p subjectAltName %s\n", cert, name );
struct x509_san_link* link = zalloc ( sizeof ( struct x509_san_link ) );
link->name = name;
list_add ( &link->list, &subject_alt_name->names );
}
asn1_skip_any ( &cursor );
}
return 0;
}
/** "id-kp-codeSigning" object identifier */
static uint8_t oid_code_signing[] = { ASN1_OID_CODESIGNING };
/** "id-kp-OCSPSigning" object identifier */
static uint8_t oid_ocsp_signing[] = { ASN1_OID_OCSPSIGNING };
/** Supported key purposes */
static struct x509_key_purpose x509_key_purposes[] = {
{
.name = "codeSigning",
.bits = X509_CODE_SIGNING,
.oid = ASN1_OID_CURSOR ( oid_code_signing ),
},
{
.name = "ocspSigning",
.bits = X509_OCSP_SIGNING,
.oid = ASN1_OID_CURSOR ( oid_ocsp_signing ),
},
};
/**
* Parse X.509 certificate key purpose identifier
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_key_purpose ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_extended_key_usage *ext_usage = &cert->extensions.ext_usage;
struct x509_key_purpose *purpose;
struct asn1_cursor cursor;
unsigned int i;
int rc;
/* Enter keyPurposeId */
memcpy ( &cursor, raw, sizeof ( cursor ) );
if ( ( rc = asn1_enter ( &cursor, ASN1_OID ) ) != 0 ) {
DBGC ( cert, "X509 %p invalid keyPurposeId:\n", cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
/* Identify key purpose */
for ( i = 0 ; i < ( sizeof ( x509_key_purposes ) /
sizeof ( x509_key_purposes[0] ) ) ; i++ ) {
purpose = &x509_key_purposes[i];
if ( asn1_compare ( &cursor, &purpose->oid ) == 0 ) {
DBGC2 ( cert, "X509 %p has key purpose %s\n",
cert, purpose->name );
ext_usage->bits |= purpose->bits;
return 0;
}
}
/* Ignore unrecognised key purposes */
return 0;
}
/**
* Parse X.509 certificate extended key usage
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_extended_key_usage ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
int rc;
/* Enter extKeyUsage */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse each extended key usage in turn */
while ( cursor.len ) {
if ( ( rc = x509_parse_key_purpose ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
}
return 0;
}
/**
* Parse X.509 certificate OCSP access method
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_ocsp ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct x509_ocsp_responder *ocsp = &cert->extensions.auth_info.ocsp;
struct asn1_cursor cursor;
int rc;
/* Enter accessLocation */
memcpy ( &cursor, raw, sizeof ( cursor ) );
if ( ( rc = asn1_enter ( &cursor, ASN1_IMPLICIT_TAG ( 6 ) ) ) != 0 ) {
DBGC ( cert, "X509 %p OCSP does not contain "
"uniformResourceIdentifier:\n", cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
/* Record URI */
ocsp->uri = zalloc ( cursor.len + 1 /* NUL */ );
if ( ! ocsp->uri )
return -ENOMEM;
memcpy ( ocsp->uri, cursor.data, cursor.len );
DBGC2 ( cert, "X509 %p OCSP URI is %s:\n", cert, ocsp->uri );
return 0;
}
/** "id-ad-ocsp" object identifier */
static uint8_t oid_ad_ocsp[] = { ASN1_OID_OCSP };
/** Supported access methods */
static struct x509_access_method x509_access_methods[] = {
{
.name = "OCSP",
.oid = ASN1_OID_CURSOR ( oid_ad_ocsp ),
.parse = x509_parse_ocsp,
},
};
/**
* Identify X.509 access method by OID
*
* @v oid OID
* @ret method Access method, or NULL
*/
static struct x509_access_method *
x509_find_access_method ( const struct asn1_cursor *oid ) {
struct x509_access_method *method;
unsigned int i;
for ( i = 0 ; i < ( sizeof ( x509_access_methods ) /
sizeof ( x509_access_methods[0] ) ) ; i++ ) {
method = &x509_access_methods[i];
if ( asn1_compare ( &method->oid, oid ) == 0 )
return method;
}
return NULL;
}
/**
* Parse X.509 certificate access description
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_access_description ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
struct asn1_cursor subcursor;
struct x509_access_method *method;
int rc;
/* Enter keyPurposeId */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Try to identify access method */
memcpy ( &subcursor, &cursor, sizeof ( subcursor ) );
asn1_enter ( &subcursor, ASN1_OID );
method = x509_find_access_method ( &subcursor );
asn1_skip_any ( &cursor );
DBGC2 ( cert, "X509 %p found access method %s\n",
cert, ( method ? method->name : "<unknown>" ) );
/* Parse access location, if applicable */
if ( method && ( ( rc = method->parse ( cert, &cursor ) ) != 0 ) )
return rc;
return 0;
}
/**
* Parse X.509 certificate authority information access
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_authority_info_access ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
int rc;
/* Enter authorityInfoAccess */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse each access description in turn */
while ( cursor.len ) {
if ( ( rc = x509_parse_access_description ( cert,
&cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
}
return 0;
}
/** "id-ce-basicConstraints" object identifier */
static uint8_t oid_ce_basic_constraints[] =
{ ASN1_OID_BASICCONSTRAINTS };
/** "id-ce-keyUsage" object identifier */
static uint8_t oid_ce_key_usage[] =
{ ASN1_OID_KEYUSAGE };
/** "id-ce-keyUsage" object identifier */
static uint8_t oid_ce_subject_alt_name[] =
{ ASN1_OID_SUBJECTALTNAME };
/** "id-ce-extKeyUsage" object identifier */
static uint8_t oid_ce_ext_key_usage[] =
{ ASN1_OID_EXTKEYUSAGE };
/** "id-pe-authorityInfoAccess" object identifier */
static uint8_t oid_pe_authority_info_access[] =
{ ASN1_OID_AUTHORITYINFOACCESS };
/** Supported certificate extensions */
static struct x509_extension x509_extensions[] = {
{
.name = "basicConstraints",
.oid = ASN1_OID_CURSOR ( oid_ce_basic_constraints ),
.parse = x509_parse_basic_constraints,
},
{
.name = "keyUsage",
.oid = ASN1_OID_CURSOR ( oid_ce_key_usage ),
.parse = x509_parse_key_usage,
},
{
.name = "subjectAltName",
.oid = ASN1_OID_CURSOR ( oid_ce_subject_alt_name ),
.parse = x509_parse_subject_alt_name,
},
{
.name = "extKeyUsage",
.oid = ASN1_OID_CURSOR ( oid_ce_ext_key_usage ),
.parse = x509_parse_extended_key_usage,
},
{
.name = "authorityInfoAccess",
.oid = ASN1_OID_CURSOR ( oid_pe_authority_info_access ),
.parse = x509_parse_authority_info_access,
},
};
/**
* Identify X.509 extension by OID
*
* @v oid OID
* @ret extension Extension, or NULL
*/
static struct x509_extension *
x509_find_extension ( const struct asn1_cursor *oid ) {
struct x509_extension *extension;
unsigned int i;
for ( i = 0 ; i < ( sizeof ( x509_extensions ) /
sizeof ( x509_extensions[0] ) ) ; i++ ) {
extension = &x509_extensions[i];
if ( asn1_compare ( &extension->oid, oid ) == 0 )
return extension;
}
return NULL;
}
/**
* Parse X.509 certificate extension
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_extension ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
struct asn1_cursor subcursor;
struct x509_extension *extension;
int is_critical = 0;
int rc;
/* Enter extension */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Try to identify extension */
memcpy ( &subcursor, &cursor, sizeof ( subcursor ) );
asn1_enter ( &subcursor, ASN1_OID );
extension = x509_find_extension ( &subcursor );
asn1_skip_any ( &cursor );
DBGC2 ( cert, "X509 %p found extension %s\n",
cert, ( extension ? extension->name : "<unknown>" ) );
/* Identify criticality */
if ( asn1_type ( &cursor ) == ASN1_BOOLEAN ) {
is_critical = asn1_boolean ( &cursor );
if ( is_critical < 0 ) {
rc = is_critical;
DBGC ( cert, "X509 %p cannot parse extension "
"criticality: %s\n", cert, strerror ( rc ) );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
asn1_skip_any ( &cursor );
}
/* Handle unknown extensions */
if ( ! extension ) {
if ( is_critical ) {
/* Fail if we cannot handle a critical extension */
DBGC ( cert, "X509 %p cannot handle critical "
"extension:\n", cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return -ENOTSUP_EXTENSION;
} else {
/* Ignore unknown non-critical extensions */
return 0;
}
};
/* Extract extnValue */
if ( ( rc = asn1_enter ( &cursor, ASN1_OCTET_STRING ) ) != 0 ) {
DBGC ( cert, "X509 %p extension missing extnValue:\n", cert );
DBGC_HDA ( cert, 0, raw->data, raw->len );
return rc;
}
/* Parse extension */
if ( ( rc = extension->parse ( cert, &cursor ) ) != 0 )
return rc;
return 0;
}
/**
* Parse X.509 certificate extensions, if present
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_extensions ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_cursor cursor;
int rc;
/* Enter extensions, if present */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_enter ( &cursor, ASN1_EXPLICIT_TAG ( 3 ) );
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse each extension in turn */
while ( cursor.len ) {
if ( ( rc = x509_parse_extension ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
}
return 0;
}
/**
* Parse X.509 certificate tbsCertificate
*
* @v cert X.509 certificate
* @v raw ASN.1 cursor
* @ret rc Return status code
*/
static int x509_parse_tbscertificate ( struct x509_certificate *cert,
const struct asn1_cursor *raw ) {
struct asn1_algorithm **algorithm = &cert->signature_algorithm;
struct asn1_cursor cursor;
int rc;
/* Record raw tbsCertificate */
memcpy ( &cursor, raw, sizeof ( cursor ) );
asn1_shrink_any ( &cursor );
memcpy ( &cert->tbs, &cursor, sizeof ( cert->tbs ) );
/* Enter tbsCertificate */
asn1_enter ( &cursor, ASN1_SEQUENCE );
/* Parse version, if present */
if ( asn1_type ( &cursor ) == ASN1_EXPLICIT_TAG ( 0 ) ) {
if ( ( rc = x509_parse_version ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
}
/* Parse serialNumber */
if ( ( rc = x509_parse_serial ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
/* Parse signature */
if ( ( rc = asn1_signature_algorithm ( &cursor, algorithm ) ) != 0 ) {
DBGC ( cert, "X509 %p could not parse signature algorithm: "
"%s\n", cert, strerror ( rc ) );
return rc;
}
DBGC2 ( cert, "X509 %p tbsCertificate signature algorithm is %s\n",
cert, (*algorithm)->name );
asn1_skip_any ( &cursor );
/* Parse issuer */
if ( ( rc = x509_parse_issuer ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
/* Parse validity */
if ( ( rc = x509_parse_validity ( cert, &cursor ) ) != 0 )
return rc;
asn1_skip_any ( &cursor );
/* Parse subject */
if ( ( rc = x509_parse_subject ( cert, &cursor ) ) != 0 )